Gruesome video clips showing Syrian rebels throwing a man from the roof of a building or brutally slaying a man appeared Monday on the Internet and sparked outrage from human rights activists.

These three videos posted on Youtube appear to have been shot in the northern region of Aleppo.

The Syrian rebels have been accused of violations of human rights and murder. One of the clips shows a crowd shouting "Allah Akbar" (God is greatest) while they were gathering around several bodies lying on the floor minutes before three victims are thrown from the roof of a building. "These are the 'Bab al-Heroes' who are in the post office building," said the videographer. When the first body is thrown, the crowd shouts" this is a Shabbih "(a pro-government militia member).

The incident seems to take place in the town of al-Bab, north of Aleppo, near the border with Turkey, but it was not possible to verify the date of this horrific scene.

In another amateur video, a man, blindfolded and hands tied behind his back, is trying to resist when a group of people forcing him to lie on the floor. They yelled at him "Sit" and he shouted: "I prefer to be killed by a bullet "but another retorted: "No, shut up." While people also cry "Allah Akbar", a man appears with a small knife, and then cut the throat and the victim's blood spilled on the floor. "This is the fate of all those who support the Shabbiha of Bashar (Assad)," said the cameraman. He added "Hamdoulillah" (praise God) and ask the butcher to stop that. "O Bashar, this is the fate of your army and your Shabbiha," said the cameraman. In the third clip, shot in Azaz in the province of Aleppo, a man with a beard came out of a car with hands tied behind and thrown to the ground. A man shoots at him with a pistol and the other ends with a machine gun. They shoot him several times and the victim dies facing the ground.

"If this video is authenticated, these atrocities undermine the revolution. This benefits the regime and the revolution's enemies inside and outside" Syria, said to Abdel Rahman head of the Syrian Observatory for Human Rights told AFP.